1. Field of the Invention
The invention is related generally to vial adapters of the type used in the transfer of medical fluids between a vial and another medical fluid container, and more particularly, to vented vial adapters useful for safe reconstitution and withdrawal of cytotoxic medicament from vials.
2. Description of the Related Art
Access ports for injecting fluid into or removing fluid from a container, such as a drug vial, are well known and widely used. Conventional seals of drug vials generally involve a pierceable rubber stopper formed of an elastomeric material such as butyl rubber or the like, placed in the opening of the vial. A closure, typically formed of metal, is crimped over the rubber stopper and the flange of the vial to positively hold the stopper in place in the opening of the vial. The closure has an outer size, known as a “finish size.” A sharp cannula is inserted through the rubber stopper to position the distal, open end of the cannula past the rubber stopper to establish fluid connection with the interior of the vial. In the case of certain medications, such as those used for chemotherapy or nuclear medicine, the rubber stopper is made thicker so that increased protection is provided against leakage.
Vial adapters have been found useful in that they can attach the sharpened cannula that is used to pierce the stopper and move far enough into the vial interior to establish fluid communication with the vial, to the connection device of another fluid container or fluid conduction device. For example, the adapter may include a female Luer fitting opposite the sharpened cannula to receive the male luer of a syringe. The “adapter” therefore adapts the vial to the syringe, or adapts the sharpened cannula to the male luer of the syringe.
It has also been found useful in some applications to provide a means to attach or anchor the adapter to the vial to hold it in place while fluid communication between the vial and another device proceeds so that inadvertent disengagement of the adapter from the vial does not occur. For example, the adapter may have arms that engage the neck or flange of the vial and hold the adapter in place on the vial. Other means include a circular slotted housing that fits around the outside of the vial closure and snaps onto the vial closure under the crimped retaining cap on the under-surface of the vial's flange thereby grasping the vial neck flange and the underside of the closure. The circular housing typically has a plurality of claws or other retaining devices that are positioned under the flange of the vial opening thereby interfering with removal of the adapter from the vial.
It has also been found useful in some applications to have a valve placed in the adapter to result in a closed system. The valved adapter permits engagement of the sharpened cannula with the contents of the vial without leakage of fluid from the vial through the adapter until the valve is purposely opened via a syringe, for example. Then when the second fluid device has been prepared, it can be connected to the adapter thereby opening or activating the valve that then permits fluid flow between the vial and second fluid device.
Vials made of glass or polymeric materials, the walls of which are non-collapsible, require an air inlet when medical fluid is withdrawn to prevent the formation of a partial vacuum in the vial. Such a partial vacuum inhibits fluid withdrawal from the vial. Typically, adapters for use with such vials have a sharpened cannula that includes both a medicament fluid lumen and a vent lumen therein. The vent fluid lumen provides pressure equalization when fluid is added to the vial or is withdrawn from the vial so that such fluid movement occurs smoothly.
Many medicaments are prepared, stored, and supplied in dry or lyophilized form in glass vials. Such medicaments must be reconstituted at the time of use by the addition of a diluent thereto. Various methods of adding the diluent to the dry or lyophilized medicament have been used over the years. One method that is commonly used is the vial adapter technique in which the diluent that may be contained in a bottle or a syringe is connected to the vial adapter which has a sharpened cannula. Once connected to the diluent container, the sharpened cannula is then forced through the closure and rubber septum of the vial to communicate the diluent to the dry or lyophilized medicament residing in the vial. After reconstitution, the liquid is usually withdrawn from the vial into the intravenous solution bottle or syringe, or other container for administration to the patient through an intravenous (“IV”) administration set or by other means.
For such reconstitution activities, a vented vial adapter is used to avoid any difficulties with a partial vacuum or high pressure inside the vial, as discussed above. These are sometimes known as pressure-equalizing vial adapters. However, with some vented vial adapters this technique is unsatisfactory because both the dry or lyophilized material and the diluent can be exposed to ambient airborne bacterial contamination during withdrawal of the reconstituted medical fluid if a filter is not present in the vial adapter.
During the reconstitution process of certain medical fluids, such as chemotherapy fluids or nuclear medicines, it is also desirable to avoid contamination of the surrounding air resulting from the formation of aerosols or drops in the vial. As used herein, aerosols are suspensions of solid or liquid particles in a gas, such as air. Contamination is possible during the injection of the diluent into the vial because more material is being added to the closed space of the vial and therefore, the vent of the adapter must channel away an equal amount of air from the vial to make room for the additive. If this air removed from the vial is channeled to the outside atmosphere, such contamination can lead to problems, among other things, in the form of allergic reactions in the exposed personnel, especially when the air is contaminated with cytotoxic drugs, chemotherapeutic drugs, anesthetics, media containing isotopes, and allergy inducing substances of various kinds.
It would also be desirable to provide a vented vial adapter for use with non-collapsible containers that is designed to prevent aerosolizing of liquid material into the ambient atmosphere as reconstitution occurs. It is desirable for the person performing the procedures to avoid contacting the medications, especially the inhalation of aerosolized medications. A vial adapter with sufficient venting and filtering is necessary to avoid such aerosolizing.
In prior vented vial adapters, a vent lumen in the sharpened cannula leads to a filter that opposes the entry of particulate matter and bacteria into the vial during medicament withdrawal or aspiration. The filter also opposes venting to the outside atmosphere. A disadvantage of prior devices is their limited ability to retain aerosols of medicament. Typical adapters employ a membrane filter formed with a pore size of about 0.2 microns. Aerosols of many medications are known to pass through such filters.
Hence, those skilled in the art have recognized a need for a pressure-equalizing vial adapter having a filter for preventing bacteria and other contaminants from reaching the contents of the vial during withdrawal of the reconstituted contents of the vial contents, and having improved aerosol retention capability so that reconstituted contents of the vial that become aerosolized do not escape the vial to the ambient environment. The present invention fulfills these needs and others.